There are many links between exposure to environmental pollution and risks to human health. While advances in the fields of toxicology, exposure science, and environmental chemistry have shown light on many of these links, many more research challenges remain. One major challenge is how to accurately characterize the toxicity of...
The importance of pheromones in insect control relies both on
their ability to reduce pest populations and on their relatively benign
effects on nontarget organisms. This study was conducted to test the
effectiveness of a pheromone application for mating disruption of the
ponderosa pine tip moth, Rhyacionia zozana (Kearfott), and...
This research assessed the effect of western juniper (Junlperus
occldentalls) removal on understory plant production and cover and
ponderosa pine (Pinus ponderosa) growth and plant water status.
A complete randomized block design, with four blocks and four
treatments was established in the summer of 1984 near Prineville,
Oregon. The four...
The objective of this research was to determine which
environmental resources, light, water, and nutrients,
control understory plant production and composition in a
Pinus ponderosa forest in northeastern Oregon. A split-plot
experimental design, with three blocks, four
treatments, and 44 plots, was established in the summer of
1985. Twenty plots...
Seasonal trends in forage production and environmental parameters
for five plant community types within a northeastern Oregon riparian zone
were described and modeled using correlation and path analysis. Wet
meadows produced the greatest amount of herbage biomass, followed by moist
bluegrass meadows, gravel bars, forests and dry bluegrass meadows. Trends...
In this work, we first introduce a novel approach to the long term irrigation scheduling
using Genetic Algorithms (GAs). We explore the effectiveness of GAs in the context of
optimizing nonlinear crop models and describe application requirements and implementation of
the technique. GAs were found to converge quickly to near-optimal...
The ability of northern goshawks (Accipiter gentilis) to persist in intensively
managed and selectively harvested forest habitats is largely unknown. To address the
concern that populations of northern goshawks in eastern Oregon may be declining in
response to habitat alteration, I studied occupancy rates and habitat relationships of
nesting goshawks...
Xylem conducting tissue or sapwood is an important storage organ
for water, carbohydrates, and nutrients, and this storage helps trees
accommodate environmental change. However, the living ray parenchyma
cells in sapwood, which store the carbohydrates and nutrients,
require energy for maintenance. I examined how sapwood maintenance
costs vary among species,...
Recreation benefits are improved personal and social
conditions which are thought to occur as a result of recreation participation. If these improved conditions
can be adequately identified and measured, then they can be applied to recreation policy and planning decisions.
Little research has been done on recreation benefits.
Much of...
Trees that survive disturbances can form a prominent legacy which may influence
post-disturbance successional pathways. The effects of biological legacies on community
dynamics is a critical question in ecology. In the present study, I examined two mapped
stands in which old-growth remnant trees, survivors of partial fires, emerge above a...